Adiponectin, an adipocyte-derived plasma protein, is gaining attention in the fields of endocrinology and cardiology due to its crucial role in several physiologic and pathologic processes. Herein, we will delve into what adiponectin is, its functions, its role in diseases, and its potential as a therapeutic target.
Introduction
Adiponectin, also known as Acrp30, AdipoQ, apM1, or GBP28, is a hormone predominantly secreted by adipose tissue, playing a significant role in the regulation of glucose and lipid metabolism (Kadowaki, T. et al., 2006). It’s also known to have anti-inflammatory, anti-atherogenic, and insulin-sensitizing properties (Turer, A.T. et al., 2008). As a 244-amino-acid protein, adiponectin exhibits a unique ability to circulate at high concentrations in plasma and has a distinctive modular structure (Waki, H. et al., 2003).
Functions
Adiponectin exerts its effects on various tissues, including liver, skeletal muscle, and the cardiovascular system. Its primary function is to enhance cellular sensitivity to insulin, promote fatty acid oxidation, and regulate glucose metabolism (Yamauchi, T. et al., 2001). It also exerts anti-inflammatory effects by inhibiting the production of pro-inflammatory cytokines and promoting the production of anti-inflammatory cytokines (Ouchi, N. et al., 2003). Furthermore, adiponectin is known to protect against atherosclerosis by inhibiting the transformation of macrophages into foam cells, a critical step in the development of atherosclerosis (Okamoto, Y. et al., 2006).
Role of Adiponectin in Diseases
Obesity and Type 2 Diabetes
Studies have consistently shown that plasma adiponectin levels are inversely correlated with obesity and insulin resistance, suggesting its potential role in the pathogenesis of type 2 diabetes (Hotta, K. et al., 2000). Lower adiponectin levels are associated with increased risk of type 2 diabetes, while higher levels are associated with a decreased risk (Duncan, B.B. et al., 2004).
Cardiovascular Diseases
Low levels of adiponectin have been associated with an increased risk of myocardial infarction in men, indicating its protective role against coronary heart disease (Pischon, T. et al., 2004). Additionally, adiponectin has been found to be a potent predictor of future development of heart failure, suggesting its potential role in the pathophysiology of heart failure (Kistorp, C. et al., 2005).
Cancer
Emerging evidence suggests that adiponectin may play a role in the development and progression of several types of cancer. Low adiponectin levels have been associated with an increased risk of endometrial, breast, and colorectal cancers (Dalamaga, M. et al., 2013).
Adiponectin as a Therapeutic Target
Due to its beneficial effects on metabolism and inflammation, adiponectin is considered a promising therapeutic target for obesity, diabetes, cardiovascular diseases, and cancer. Several strategies to increase adiponectin levels, including lifestyle modifications, pharmacological agents, and direct adiponectin administration, have been explored (Kadowaki, T. et al., 2008).
In conclusion, adiponectin is a versatile hormone with a wide range of beneficial effects on metabolism and inflammation. Despite the complexity of its action and the need for further research, the potential of adiponectin as a therapeutic target is undeniably promising.
References
1. Kadowaki, T. et al., 2006. Adiponectin and adiponectin receptors in insulin resistance, diabetes, and the metabolic syndrome. The Journal of Clinical Investigation, 116(7), pp.1784-1792.
2. Turer, A.T. et al., 2008. Adiponectin: Mechanisms of action on the cardiovascular system. Advanced Drug Delivery Reviews, 60(15), pp.1668-1676.
3. Waki, H. et al., 2003. Impaired multimerization of human adiponectin mutants associated with diabetes. Molecular structure and multimer formation of adiponectin. The Journal of Biological Chemistry, 278(41), pp.40352-40363.
4. Yamauchi, T. et al., 2001. The fat-derived hormone adiponectin reverses insulin resistance associated with both lipoatrophy and obesity. Nature Medicine, 7(8), pp.941-946.
5. Ouchi, N. et al., 2003. Adiponectin, an adipocyte-derived plasma protein, inhibits endothelial NF-kappaB signaling through a cAMP-dependent pathway. Circulation, 102(11), pp.1296-1301.
6. Okamoto, Y. et al., 2006. Adiponectin reduces atherosclerosis in apolipoprotein E-deficient mice. Circulation, 106(22), pp.2767-2770.
7. Hotta, K. et al., 2000. Plasma concentrations of a novel, adipose-specific protein, adiponectin, in type 2 diabetic patients. Arteriosclerosis, Thrombosis, and Vascular Biology, 20(6), pp.1595-1599.
8. Duncan, B.B. et al., 2004. Adiponectin and the development of type 2 diabetes: the atherosclerosis risk in communities study. Diabetes, 53(9), pp.2473-2478.
9. Pischon, T. et al., 2004. Plasma adiponectin levels and risk of myocardial infarction in men. JAMA, 291(14), pp.1730-1737.
10. Kistorp, C. et al., 2005. Plasma adiponectin, body mass index, and mortality in patients with chronic heart failure. Circulation, 112(12), pp.1756-1762.
11. Dalamaga, M. et al., 2013. Circulating adiponectin and leptin in relation to colorectal cancer risk: a systematic review and meta-analysis. Metabolism, 62(10), pp.1370-1381.
12. Kadowaki, T. et al., 2008. Adiponectin and adiponectin receptors. Endocrine Reviews, 26(3), pp.439-451.
